1. Field of the Invention
Aspects of the invention relate to a multifunction apparatus provided with an image recording unit having a discharge tray disposed on a top face thereof and an image reading unit disposed on the image recording unit.
2. Description of Related Art
Multifunction apparatuses in general are provided with a printer unit for recording an image on a recording sheet and a scanner unit for reading an image of a document. Some of the multifunction apparatuses have a facsimile function and a card reader function. The printer unit is provided with a sheet feed cassette for housing recording sheets, a discharge tray for retaining recording sheets on which images are recorded, a transfer path for transferring the recording sheets from the sheet feed cassette to the discharge tray, and an image recording engine for recording images on the recording shoots in the transfer path. The scanner unit is an FBS (Flatbed Scanner) for reading an image of a document by the use of an image sensor such as a CIS (Contact Image Sensor) and a CCD (Charge Coupled Device) which reciprocates along a platen glass.
The printer unit is connected to a computer or the like to perform image recording based on print data sent from the computer. In the case of using the printer unit, a user inputs an instruction for printing a desired text or image to the computer. Upon reception of the print instruction input, the computer creates print data to send the print data to the printer unit. Upon reception of the print data by the printer unit, a recording sheet is fed from the sheet feed cassette to the transfer path. Then, the image recording engine records the image on the recording sheet based on the print data. Then, the recording sheet after the image recording is discharged to the discharge tray. The user takes out the image-recorded recording sheet discharged on the discharge tray.
In the case of using the scanner unit, the user opens a document cover to place a document on the platen glass and then closes the document cover to input an instruction of starting reading. When the scanner unit receives the reading start instruction, the image sensor moves along the platen glass to read an image of the document. After the image reading, the user opens the document cover again to collect the document placed on the platen glass. In the case of copying, the image data read by the scanner unit is sent to the printer unit, and then the printer unit performs the image recording on a recording sheet based on the image data in the same manner as described above. After that, the user takes out the image-recorded recording sheet from the discharge tray.
In view of the usages of the printer unit and the scanner unit, it is preferable that the scanner unit is disposed at an uppermost part since the open/close of the document cover and the placement/collection of document are conducted in the scanner unit. Also, in order to downsize an installation space of the multifunction apparatus, it is preferable that the scanner unit and the printer unit are disposed one above the other along a vertical direction and that the sheet feed cassette and the discharge tray of the printer unit do not project in a horizontal direction from the apparatus. From such viewpoints, a structure wherein: the scanner unit is disposed on the printer unit; the scanner unit and the printer unit are disposed with a space being defined therebetween; and the discharge tray is disposed in the space is generally employed.
Since the space for disposing the discharge tray is defined below the scanner unit, a part of a casing of the scanner unit corresponding to the space tends to be changed in shape. For example, a book of a heavy weight is placed on the platen glass of the scanner unit as being opened on the platen glass for image reading in some cases. Since a binding part of the book tends to be detached from the platen glass, the user might press the binding part against the platen glass for the image reading. When the book is pressed against the platen glass, the weight of the book and the pressure applied by the user act as a load on the platen glass and the casing of the scanner unit. When the load is too large, the platen glass and the casing can be deformed or damaged. Therefore, it is necessary for the casing of the scanner unit to have a rigidity which can bare the load.
Because of this, among multifunction apparatuses of the related art, there is that in which a casing support member for supporting the casing of a scanner unit is coupled to an electric equipment housing unit for housing an electric equipment unit by the use of a coupling member to establish a honeycomb shape between the casing support member and the electric equipment housing unit, thereby increasing a rigidity of the casing.
However, in the structure where the discharge tray of the printer unit is disposed below the scanner unit, it is undesirable to dispose a member projecting from an underside of the casing of the scanner unit or a member crossing on the discharge tray since such members interfere a recording sheet to be discharged to the discharge tray.